Abstract

Most available studies on lead smelter emissions deal with the environmental impact of outdoor particles,
but only a few focus on air quality at workplaces. The objective of this study is to physically and chemically
characterize the Pb-rich particles emitted at different workplaces in a lead recycling plant. A multiscale
characterization was conducted from bulk analysis to the level of individual particles, to assess the
particles properties in relation with Pb speciation and availability. Process PM from various origins were
sampled and then compared; namely Furnace and Refining PM respectively present in the smelter and at
refinery workplaces, Emissions PM present in channeled emissions.
These particles first differed by their morphology and size distribution, with finer particles found in
emissions. Differences observed in chemical composition could be explained by the industrial processes.
All PM contained the same major phases (Pb, PbS, PbO, PbSO4 and PbO·PbSO4) but differed on the nature
and amount of minor phases. Due to high content in PM, Pb concentrations in the CaCl2 extractant reached
relatively high values (40mgL−1). However, the ratios (soluble/total) of CaCl2 exchangeable Pb were
relatively low (<0.02%) in comparison with Cd (up to 18%). These results highlight the interest to assess
the soluble fractions of all metals (minor and major) and discuss both total metal concentrations and
ratios for risk evaluations. In most cases metal extractability increased with decreasing size of particles,
in particular, lead exchangeability was highest for channeled emissions.
Such type of study could help in the choice of targeted sanitary protection procedures and for further
toxicological investigations. In the present context, particular attention is given to Emissions and Furnace
PM. Moreover, exposure to other metals than Pb should be considered.